Saylor had a capital balance of $168,000 at the beginning of the period. At the end of the accounting period, the capital balance was $198,000 ?

Very simple: Where there is no addition to or withdrawal from the Investments during the period, the entire Increase is the result of the net profit during the period. 

In this case, the net income is : Capital Balance at End of the period - Capital balance at the beginning of the period = $198,000 - $ 168,000 = $ 30,000

If there is no addition to the capital, it is supposed to be n Net income 30,000

Net Income = 30,000 [[[[[[[ 

Is it a netincome of,